INTERBREEDING CONDITIONS FOR EXPLAINING NEANDERTHAL DNA IN LIVING HUMANS: THE NONNEUTRAL CASE

摘要

We consider here an extension of a previous work by Neves and Serva, still unpublished, which estimates the amount of interbreeding between anatomically modern Africans and Neanderthals necessary for explaining the experimental fact that 1 to 4% of the DNA in non-African living humans is of Neanderthal origin. In that work we considered that Africans and Neanderthals had the same fitness (neutral hypothesis) and Neanderthal extinction was thus an event of fortune. In this work we consider that Africans had larger fitnesses. We show results for four values for the fitness difference: 1%, 5%, 10% and 20% and compare them with the corresponding neutral results. Some technical differences with respect to the neutral case appear. We conclude that even with 1% fitness difference Neanderthals extinction comes up in too small a time, so the neutral model looks more suitable for explaining the known data on occupation of some caves in Israel for a very long time, alternately by Africans and Neanderthals.